The invention relates to surgical systems applying thermal energy to biological tissue to modify the characteristics of the tissue. More particularly, the invention is directed to electrosurgical probes utilizing radiofrequency (RF) energy to cut, coagulate, ablate and/or vaporize the tissue during a medical procedure for treatment and therapy.
Arthroscopic surgery is becoming increasingly popular, because it generally does less damage, is less invasive and is safer than open procedures and produces less scarring in and around joints. This type of surgery further results in a faster healing response and a quicker return of the patient to full productivity while reducing costs of open surgical procedures.
Nevertheless, arthroscopic surgery has its limitations. The surgeon must operate through a narrow tube, which is awkward. Only one probe can be used at a time. Often the viewing camera is positioned at an angle which is different from the surgeon""s normal gaze. This contrasts with xe2x80x9copen surgeryxe2x80x9d where the surgeon has relative ease of viewing the surgical site and can freely move both hands, even utilizing the hands of colleagues.
In view of such difficulties of arthroscopic surgery, it is understandable that laser, microwave and radiofrequency (RF) probes which simultaneously cut and coagulate are preferred. However, current probes are poorly adapted to certain activities, such as cutting narrow tendons or ligaments. Current probes have convex, pointed and/or flat tips. Other probes such as those utilizing laser energy delivery systems often provide pointed tips with curved configurations. with current probes, the surgeon has little control when pressing against a tough ligament. Now as the surgeon cuts through one portion of the ligament, the probe slips out of position. The surgeon must reapproximate the probe and cut again, an inefficient process. Unless the surgeon is able to stop pressure at exactly the right time, the probe may slip and cut an adjacent structure. Because the surgeon must repeatedly reapproximate and cut the ligament, the surgeon has difficulty in cleanly ablating the ligament or tendon. Thus, there are certain procedures that surgeons still prefer to perform in an open setting which is conventionally termed an xe2x80x9copenxe2x80x9d procedure. Unfortunately, this often results in large scars, long convalescence, and even more irritation of an already irritated joint.
What is needed is a probe that can simultaneously direct the tendon to the energy source (e.g., RF) and apply RF to cleanly and smoothly ablate the tendon or ligament. The advantage is that some procedures that have been considered too awkward or difficult to perform by arthroscopy can now be performed more effectively using arthroscopic devices.
Moreover, conventional and more complex surgical probes and lasers are less suitable for critical and precise shaping and sculpting of body tissues such as articular cartilage, ligaments and tendons. Target tissues subject to ablation and removal have many different configurations and structures. These medical device probes and lasers have further disadvantages of being configured for simple ablation without regard to the contour and structure of the target tissue. By universally applying RF energy to the site, non-target tissue may be affected by collateral thermal effects.
For these reasons, it would be desirable for an apparatus and method to selectively cut and ablate body tissue during a medical procedure such as arthroscopic surgery. The apparatus and method should be configured and used for effective cutting, ablation and vaporization of target tissue while giving the surgeon a precise and controlled surface for scraping tissue from bone or sculpting tissue within the surgical field for appropriate treatment and therapy. Such apparatus and methods should also be applicable in a wide variety of medical procedures on a wide range of different bodily tissues. The apparatus should also be simple and less expensive to manufacture while being compatible with conventional systems and procedures.
One embodiment of the invention is based on a surgical apparatus, comprising: an energy application tip including: a length of shaft; and an active electrode having a curved current density edge with at least one convex surface.
Another embodiment of the invention is based on a method of surgically treating a mammal in need thereof, comprising: providing a surgical instrument including a length of shaft and an active electrode having a curved current density edge with at least one convex surface; and ablating a tissue surface with said surgical instrument.
Another embodiment of the invention is based on an electrosurgical system for directing thermal energy to tissue is disclosed which has a power supply and a probe. The probe is coupled to the power supply by a cabling means and has a handle and a shaft including a distal end and a proximal end. The shaft has at least one lumen for an active electrode electrically coupled to the power supply, the active electrode being positioned on the distal end of the probe, the active electrode having an energy application surface; and a return electrode electrically coupled to the power supply.
These, and other, goals and embodiments of the invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention without departing from the spirit thereof, and the invention includes all such modifications.